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Experiments Show Gravity Is Not an Emergent Phenomenon
MIT Technology Review ^ | 08/24/2011 | Staff

Posted on 08/24/2011 2:52:57 PM PDT by Red Badger

The way gravity effects quantum particles proves that it cannot be an emergent phenomenon, says physicist.

One of the most exciting ideas in modern physics is that gravity is not a traditional force, like electromagnetic or nuclear forces. Instead, it is an emergent phenomenon that merely looks like a traditional force.

This approach has been championed by Erik Verlinde at the University of Amsterdam who put forward the idea in 2010. He suggested that gravity is merely a manifestation of entropy in the Universe, which always increases according to the second law of thermodynamics. This causes matter distribute itself in a way that maximises entropy. And the effect of this redistribution looks like a force which we call gravity.

Much of the excitement over Verlinde's idea is that it provides a way to reconcile the contradictions between gravity, which works on a large scale, and quantum mechanics, which works on a tiny scale.

The key idea is that gravity is essentially a statistical effect. As long as each particle is influenced by a statistically large number of other particles, gravity emerges. That's why it's a large-scale phenomenon.

But today, Archil Kobakhidze at The University of Melbourne in Australia points to a serious problem with this approach. He naturally asks how gravity can influence quantum particles.

Kobakhidze argues that since each quantum particle must be described by a large number of other particles, this leads to a particular equation that describes the effect of gravity.

But here's the thing: the conventional view of gravity leads to a different equation.

In other words, the emergent and traditional views of gravity make different predictions about the gravitational force a quantum particle ought to experience. And that opens the way for an experimental test.

As it happens, physicists have been measuring the force of gravity on neutrons for ten yeas or so. And...wait for the drum roll... the results exactly match the predictions of traditional gravitational theory, says Kobakhidze.

"Experiments on gravitational bound states of neutrons unambiguously disprove the entropic origin of gravitation," he says.

That's an impressive piece of physics. It'll be interesting to see how Verlinde and his supporters respond.

Ref: arxiv.org/abs/1108.4161: Once More: Gravity Is Not An Entropic Force


TOPICS: Culture/Society; Technical
KEYWORDS: electrogravitics; force; gravity; physics; unifiedtheory
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To: Red Badger

Gravity is merely the effect of everything growing larger.


101 posted on 08/24/2011 4:34:28 PM PDT by Yardstick
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To: Red Badger

So, I still have to go to work tomorrow?


102 posted on 08/24/2011 4:38:26 PM PDT by Unruly Human
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To: tophat9000

I had a thought about why time dilation and velocity are linked in Relativity. Imagine that time is caused by our 3 dimensional universe moving at the speed of light through a 4th dimension. We move through this 4th dimension at a constant rate and direction, which is why time seems to flow one-way at a contant rate. The kicker to this idea is, that the velocity limit of the speed of light applies to the SUM of our motion in the 3 spatial dimensions and the 4th time dimension. So, any spatial motion would have to reduce the velocity of an object through time, since everything is already moving at the speed of light in the 4th dimension. Of course, this effect wouldn’t be noticeable at everyday speeds, since they are so much smaller than the speed of light, the time distortion is negligible.

I’m still trying to work out a few things about how that could actually work, but I think it’s an interesting idea.


103 posted on 08/24/2011 4:41:43 PM PDT by Boogieman
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To: concerned about politics

My guess was that it is a property of dark matter.


104 posted on 08/24/2011 4:41:53 PM PDT by Cyman
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To: Grizzled Bear

It is probably best to just watch and enjoy “Star Trek” rather than think too much about it.

They do make some weak attempts to explain why everyone speaks American English but that has to be a big what if too.


105 posted on 08/24/2011 4:46:10 PM PDT by yarddog
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To: FredZarguna
But there is NO Physicist now alive who believes that Newtonian mechanics is fundamentally correct.

They still teach it at the colleges. I talked to a professor at the local college (because I wanted to know if he taught a class on quantum.) that didn't believe in Quantum physics at all!
If it's now considered bunk, then why the heck are students still forced to take it and pay for it?

106 posted on 08/24/2011 4:46:13 PM PDT by concerned about politics ("Get thee behind me, Liberal")
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To: Fightin Whitey
Gravity is certainly no friend of my emergent phenomenon.

Would your wife describe it as a phenomenon?

107 posted on 08/24/2011 4:49:22 PM PDT by CharacterCounts (November 4, 2008 - the day America drank the Kool-Aid)
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To: concerned about politics
Well, having taught Physics to undergrads for a number of years, the answer is this: on the ordinary scale of things useful for a very large part of physics, chemistry, biology, weak gravity astonomy, telemetry, and almost all of engineering that isn't EE, Newtonian Mechanics works perfectly well. It is an amazingly accurate approximation; the conceptualization is much simpler, and the mathematics is an order of magnitude or so easier. On these scales, for these professions, there is no reason to teach quantum mechanics, so it is not taught except for those aspects particular to a given discipline.

I don't know what your local college is, but there is no mainstream Physicist who doesn't believe in QM. None.

108 posted on 08/24/2011 4:56:19 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: Cyman
If you mean the "matter" hosed out of milking parlors, or shoveled out of horse barns, then yes, that is usually dark, and it is exactly what he's been writing about on this thread.
109 posted on 08/24/2011 4:59:15 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: Red Badger

So does this mean that there are gravitons in the universe?


110 posted on 08/24/2011 5:00:45 PM PDT by Jack Hydrazine (It's the end of the world as we know it and I feel fine!)
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To: FredZarguna
I don't know what your local college is, but there is no mainstream Physicist who doesn't believe in QM. None.

Really? Beside that one professor, at the beginning of almost every book I've read on the subject, there's always a quiet "debate" between the two sciences, as if there's some kind of scientific struggle going on behind the scenes.
I'm glad you told me that. I'm not a science major, but Quantum physics fascinates me. I'm thrilled to learn there is no more debate. It's an amazing science, but when I try to explain it to some one, the scientific jargon escapes me. (I'm not well versed in that at all.)

111 posted on 08/24/2011 5:04:10 PM PDT by concerned about politics ("Get thee behind me, Liberal")
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To: concerned about politics
There aren't two distinct sciences. Quantum Mechanics includes Newtonian Mechanics as a specialized, limited case. There is even a rule of thumb called "the Correspondence Principle" in QM which specifies that in the limit of large quantum numbers you are supposed to be able to get back to the same results as classical physics (what you are calling "Newtonian.")
112 posted on 08/24/2011 5:13:00 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: CharacterCounts

At a certain age, just “emergent” is enough.


113 posted on 08/24/2011 5:14:30 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: Red Badger

Okay . It has been long been my belief, and I am NOT a physicist, but I do watch the Science Channel and all. But it is my belief that gravity is NOT a property of matter, but matter is a property of gravity. When you look at it that way, everything changes.


114 posted on 08/24/2011 5:36:13 PM PDT by fhayek
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To: FredZarguna
Thank you for the cogent reply. But I, in my bigheadfredlessness, meant The Unification Church, where, the goal is pursued so single-mindedly and without regard for its plausibility that it takes on the aspects of zealotry. ;-)

I would like you to take a look at my book if you have any leisure time.

Bigheadfred's Incoherent And Incomprehensible Rantography

115 posted on 08/24/2011 5:36:19 PM PDT by bigheadfred (But alas)
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To: Red Badger

A Poem (by me)

Dear Mr. Buffett:

Shuffett.


116 posted on 08/24/2011 5:41:04 PM PDT by Arthur McGowan (In Edward Kennedy's America, federal funding of brothels is a right, not a privilege.)
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To: tophat9000

thanks. i think relativity, as popularly expressed, is mental masturbation.


117 posted on 08/24/2011 5:41:35 PM PDT by the invisib1e hand
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To: FredZarguna
At a certain age, just “emergent” is enough.

I know what you mean, but does everybody else????

http://www.freerepublic.com/focus/f-news/2768587/posts

118 posted on 08/24/2011 5:54:49 PM PDT by bigheadfred (But alas)
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To: FredZarguna

Maybe the folks behind this theory are quarks!


119 posted on 08/24/2011 6:21:42 PM PDT by antidemoncrat
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To: tophat9000
I came across this completely by accident, thought you might want to check it out. http://www.heraldsun.com.au/technology/hong-kong-physicists-put-an-end-to-time-travel-talk/story-fn7celvh-1226101130129
120 posted on 08/24/2011 6:27:54 PM PDT by the invisib1e hand
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